Office employees are influenced by various environmental and contextual factors that prompt interaction with building interfaces, such as adjusting windows or blinds. These behaviours can impact predictions of buildings' performance. While occupant behaviour models often rely on physical variables, they tend to overlook users' actual motivations and how these interact. This study introduces a novel mobile application, OBdrive, that uniquely captures occupants' motivations in real-time, offering direct insights into why users operate windows, blinds, and lights. OBdrive forms a central element of the eCOMBINE framework ("Interaction between energy use, COMfort, Behaviour and the INdoor Environment in office buildings"), applied across five monitoring campaigns in two open-plan offices in Switzerland. The analyses highlight the diverse range of motivations underlying occupants' interaction with windows and blinds. In addition to single environmental drivers (e.g., 45 % of window-open actions in response to warm discomfort), multi-domain discomforts often act in combination to prompt adaptive behaviours (e.g., 32 % of the recorded opening windows actions were linked to the cooccurrence of warm discomfort and poor air quality). Occupants' behaviour (e.g., window closing actions) can be linked to time-related and contextual factors, such as departing office and requirements from co-workers. The findings demonstrated that both explicit and "hidden" motivations (e.g., co-worker asked, save energy, mask noise) drive human-building interactions (HBIs), and that these motivations are rarely captured in traditional field studies. Therefore, the eCOMBINE framework, along with the OBdrive application, offers a means to unravel the combinations of motivations driving occupant behaviours in buildings.